BUDAPEST, Hungary — Threats to a string of European Olympic offices are reviving a question that has haunted preparations for the Winter Games next month: Is it safe to go to Sochi?

European Olympic authorities, whose countries have faced terrorist threats and attacks in the past, largely shrugged off the new menacing messages as a hoax, a marginal phenomenon that security experts say is common ahead of big events.

Some members of the U.S. Congress aren’t so sure. They say Russia isn’t doing enough to assure that athletes will be protected at the Feb. 7-23 games, happening not far from an Islamic insurgency that Russia’s huge security apparatus has struggled for two decades to quell.

Russia may run greater risks in towns outside the tightly controlled Olympic zone. Suicide bombs last month a few hundred kilometers (miles) away have increased concerns, and an Islamic warlord has urged his followers to attack the Sochi Olympics, Russian President Vladimir Putin’s pet project.

The threats reported Wednesday appeared to be more anodyne.

They were first revealed by Hungarian sports officials, who announced they had received an email in Russian and English threatening Hungarian athletes with terrorist attacks.

The International Olympic Committee insisted it takes credible threats seriously, but “in this case it seems like the email sent to the Hungarian Olympic Committee contains no threat and appears to be a random message from a member of the public.”

International Olympic Committee President Thomas Bach said he remains confident in Russia’s Olympic organizers.

Talking to reporters in Rio de Janeiro on Wednesday, he said: “Security is always a matter of concern, not only in the Olympic Games but at every big event, whether it’s sport or any other. That is unfortunately the world we are living in.

“But we are very confident and we know the Russian authorities together with their many partners internationally are doing everything to organize the games in a safe and secure way.”

The Hungarian Olympic Committee said it had received a message from the organizers of the Sochi Games saying: “Threat described in the email sent to your address is not real.”

It turned out that Olympic committees from several other European countries, including Britain, Germany, Italy and Austria, had received similar messages but hadn’t publicly reported them.

Wolfgang Eichler, spokesman for the Austrian National Olympic Committee, said the email was a hoax that officials had seen before.

“It’s a fake mail from a sender in Israel who has been active with various threats for a few years,” Eichler told Austrian news agency APA. “It’s been checked out because it also arrived two years ago.”

Germany’s national Olympic association, the DOSB, also said it had received “several times the same mail with unspecific, general warnings” and it had sent it onto security officials.

“We are not aware of any threats that have been deemed as credible being directed toward our delegation,” British Olympic Association spokesman Darryl Seibel told the AP. “Organizations such as ours receive email correspondence all the time — some of which seem to lack in credibility.”

A spokeswoman for Switzerland’s Olympic committee said similar threats were common so close to the Winter Games and athletes and officials would base their travel plans instead on the assessment of security officials — not on threats.

Across the Atlantic, some are viewing the Sochi Games with more trepidation. Members of Congress expressed serious concerns Sunday about the safety of Americans at next month’s Olympics in Russia and said Moscow needs to cooperate more.

While FBI Director James Comey said earlier in January that the Russian government “understands the threat and is devoting the resources to address it,” the U.S. has offered air and naval support to the Russian government as it conducts security preparations for the Olympics.

The U.S. State Department has advised Americans at the Olympics to keep vigilant about security because of potential terrorist threats, crime and uncertain medical care.

By contrast, the French Foreign Ministry for example has not issued any particular terrorism warnings for travelers to Sochi, and a French official said Wednesday that the government has seen no reason to adapt its advice for now.

All national Olympic committees “take security seriously and a number travel with their own security. It is not unusual to see the USA expressing greater concerns than other nations,” said Andrew Amery, who oversaw security for the 2012 London Olympics, noting that the U.S. sends one of the largest teams and many of the top sponsors are American companies.

Amery said intelligence services will be crucial to the games. “It is not unusual to see an increase in hoax calls during the build up to such events and the security agencies will be prepared for them. I do not feel this increases the risks in Sochi and am confident that the security agencies are well-placed to assess these threats.”

Russia has responded to the Islamic threat by introducing some of the most sweeping security measures ever seen at an international sports event, including an estimated 100,000 police, army and other security forces.